Moderator, Iberia Airlines, Airport Lounges, and Ambassador, British Airways Executive Club
Join Date: Feb 2010
Programs: BA Lifetime Gold; Flying Blue Life Platinum; LH Sen.; Hilton Diamond; Kemal Kebabs Prized Customer
Posts: 63,807
Yes it's not clear cut. I know how it happened, and I'm afraid it's a repeat of the old, old adage in this forum of always checking your ticketing (e.g. via the App or CheckMyTrip), particularly if you do this sort of change or related complexity. It's complicated since it is a requirement of EC261 to be ticketed to avail of its protections, however you will presumably have the ability to argue that it was not you that cancelled the ticket.
Realistically I think your best bet is to obtain for yourself the best alternative that meets the clause about "re-routing, under comparable transport conditions, to their final destination at the earliest opportunity", (assuming BA didn't have that option open to you) and ping them for the delay too if there was really no cost effective alternative within the timetable. I can see this could get messy. Please keep us informed.